For example, a fuel cell single cell is formed by supporting a membrane electrode assembly (MEA) including an anode electrode and a cathode electrode oppositely disposed respectively on one and the other sides of an electrolyte membrane with a frame and holding the membrane electrode assembly and the frame between a pair of separators. Such fuel cell single cells are used as a fuel cell stack in which a predetermined number of fuel cell single cells are stacked.
Fuel gas, e.g. hydrogen-based gas, is supplied to the anode electrode of the fuel cell single cell, where the hydrogen is ionized on an electrode catalyst and moved to the cathode electrode through the electrolyte membrane.
Oxidant gas, e.g. oxygen-based gas or air, is supplied to the cathode electrode, where the above-described hydrogen ion, electron and oxygen cause a reaction to generate water while the produced electron is collected to an external circuit and used as direct-current electric energy.
In the outer periphery of the fuel cell single cell, manifold parts are typically formed to penetrate the frame and the separators in the stacking direction. The reaction gases are supplied from manifold parts to the anode and cathode electrodes through the pair of separators.
JP 2005-108506A (Patent Document 1) discloses covering opening ends correspond to such a manifold parts of separators by sealing members so as to form reaction gas coupling channels in the sealing members for distributing reaction gases. It is described that the sealing members having the reaction gas coupling channels enable to form a fuel cell that does not cause a gas leakage and has high air-tightness in which flow of the reaction gases are not blocked.